Banding even in CRF19 - slower

Hello, I'm quite new in x264 encoding. But I read many messages in this forum, and I realised that simple settings give the best results: CRF, preset medium or slow and tune film. When needed, I add yadif, and sometimes hqdn3d=2:1:2 (I use mencoder only). Usually I compress some SD sources (DVD mainly) at CRF 21 and the result is quite fine. But on a quite clean source, I have some problems especially with banding. Below you can see screenshots (in PNG) from the source and the compressed version (the source and compressed clip ). Here is the command-line Code:

Another screenshots to the clip I've uploaded (link in first post): Look at the hand (thank you Captain Obvious :sly:) Source: CRF 19 - preset=slower:

use x264 10bit version or enable deband filter in ffdshow. your choice.

What a quick answer !! Thanks ! How to activate 10-bit x264 ? Will the result of the compression be still be compatible with usual players ? I do not want to impose any filter at playback (one of my constraints), so you mean deband (=gradfun) during encoding ?

10 bit video will work on pc only!

There was a similar thread regarding banding when encoding not so long ago. I'm too lazy to look for it at the moment but I was one of the posters experimenting with someone else's "problem" sample. The source contained banding but it was less obvious than after encoding it, even when using a fairly low CRF value. What I did discover was if I converted the same sample to uncompressed RGB, it still made the banding worse. I don't understand why, although I'd be curious to know if converting your video to an uncompressed/lossless format produces the same result as the source, or whether it's the encoding which is the problem.

Is your monitor calibrated? Incorrect darkness and gamma settings on your monitor can exacerbate artifacts such as banding.

x264 is not very good with preserving gradients, but it looks like there is more going on- something with decoding/color spaces.

It probably just gave the frame a lot more bits for whatever reason.

BeStBeSt's sample clip needs an average bitrate of about 1000 kbps at --preset veryslow for good results (no clearly visible banding or compression artifacts when freeze-frame comparing against the source). When using CRF encoding and --preset veryslow --tune film, I got ~1000 kbps average bitrate and about the same visible quality with these three combinations: (a) --crf 14 --aq-strength 1.2 (b) --crf 16 --qcomp 0.8 --aq-strength 1.2 (c) --crf 18 --qcomp 0.8 --aq-strength 1.5 Increasing psy-rd to 1.3 didn't have much effect on this clip. Switching to aq-mode 2 required lowering CRF by 2 to get comparable quality. If the task at hand is to balance the quality of this clip to the overall video while trying to minimize file size, playing with AQ strength and qcomp may be necessary. Or you could use zones to encode this particular scene with higher bitrate. It's hard to give specific advice without having access to the complete source video.